1. Field of the Invention
This invention relates to key operated lock systems and, more particularly, to a lock system which in one state is operable with one key, and which is operable using another key to place the lock system in a second state wherein the one key cannot be used to operate the lock system.
2. Background Art
Key operated lock systems are used in myriad different environments. Many of these lock systems are designed to be operable using multiple, different keys. Often, lock systems that are operable using different customer keys are constructed to be operable by a master key. As just one example, a dealer having on hand a yard filled with recreational vehicles or fifth wheel vehicles may wish to have a single key that permits universal access to all vehicles. This is a convenience to the dealer since a master key obviates the need to identify one specific customer key that will operate the lock system on a given vehicle.
While having a master key is a convenience to the dealer, there is a potential security risk in the event that the master key finds its way into the wrong hands. Every vehicle on the premises of the dealer and every customer purchased vehicle is at risk that the possessor of the master key will make an unauthorized use thereof.
This same problem exists with lock systems that are operable using any of multiple different keys. That is, a breach of security with a customer""s lock system may occur by the unauthorized use of a second type of key that is different than the customer""s key.
The art is replete with lock systems that are operable with multiple different keys. Some of these systems tend toward the complex. Complexity often becomes associated with increased manufacturing costs and reduced reliability.
One such lock system has a first state wherein it is operable by two different keys and a second state wherein it is operable by only one key. U.S. Pat. No. 3,257,831 shows such a structure. In this patent, operation of the lock system with one key results in the repositioning of a ring which blocks insertion of the other key.
In one form, the invention is directed to a key operated, lock actuating system having a housing and a lock cylinder that is pivotable relative to the housing around a first axis. An actuator assembly is pivotable around the first axis between a fully locked position and an unlocked position. The lock actuating system includes a first key having a first configuration and a second key having a second configuration. The lock cylinder has a keyway into which each of the first and second keys can be directed with the lock cylinder pivoted relative to the housing into a key removable position. The lock cylinder has a repositionable element which is changed from a first position into a second position as an incident of the second key being directed into the keyway. The lock cylinder is configured so that direction of the first key into the keyway does not cause the repositionable element to be placed into the second position. A first surface on the lock cylinder and a second surface on the actuator assembly cooperate to allow the lock cylinder to act against and pivot the actuator assembly in one direction around the first axis as the key cylinder is pivoted from the key removal position in the one direction to thereby move the actuator assembly from the unlocked position toward the locked position. The lock cylinder has a third surface and the actuator assembly has a fourth surface which cooperate with the repositionable element in the second position and not in the first position to allow the third surface to act against the fourth surface as the lock cylinder is pivoted oppositely to the one direction to thereby move the actuator assembly toward the key removal position. The lock cylinder is pivotable with the first key directed into the keyway, with the lock cylinder in the key removable position and the actuator assembly in the unlocked position, in the one direction around the first axis sufficiently to cause the first surface to act against and move the second surface so that the actuator assembly is placed in the fully locked position. The lock cylinder is thereafter pivotable oppositely to the one direction around the first axis to place the lock cylinder in the key removal position without changing the actuator assembly from the fully locked position. The lock cylinder is pivotable with the second key directed into the keyway with the lock cylinder in the key removal position and the actuator assembly in the unlocked position in the one direction around the first axis sufficiently to cause the first surface to act against and move the second surface so that the actuator assembly is placed in the fully locked position. The lock cylinder is thereafter pivotable oppositely to the one direction around the first axis which causes the third surface to act against the fourth surface to thereby move the actuator assembly from the fully locked position to an intermediate position between the fully locked and unlocked positions as the actuator assembly is moved into the key removal position.
In one form, the housing defines a cavity within which the lock cylinder resides.
The actuator assembly may include an extension which projects into the housing cavity and defines the fourth surface.
The repositionable element may be a wafer that is movable transversely to the first axis between the first and second positions.
In one form, the second surface faces circumferentially relative to the first axis on the actuator assembly.
In one form, with the second key directed into the keyway and the actuator assembly in the fully locked position, pivoting of the lock cylinder oppositely to the one direction causes the lock cylinder to pivot a predetermined amount before the third surface acts against the fourth surface.
In one form, the third surface is defined on the repositionable element.
In one form, there is a single piece on the actuator assembly that extends fully around the first axis and defines the second surface.
The single piece may define the fourth surface.
In one form, with the first key directed into the keyway, the lock cylinder is pivotable oppositely to the one direction to cause the third surface to move in a curved path toward and past the fourth surface.
The invention is also directed to the combination of a lock element that is movable between a secured position and an unsecured position and a key operated lock actuating system, as described above. As the actuator assembly moves from the locked position into the unlocked position, the lock element moves from the secured position into the unsecured position.
In one form, with the actuator assembly moved from the fully locked position to the intermediate position, the lock element remains in the secured position.
The lock element may be either pivotable or translatable between the secured and unsecured positions.
The actuator assembly may directly engage the lock element.
Alternatively, there is an intermediate element that is separate from and movable relative to the actuator assembly and the lock element and transmits movement between the actuator assembly and the lock element.
The invention is also directed to a method of actuating a key operated lock system. The method includes the steps of: directing a first key having a first configuration into a keyway in a lock cylinder that is pivotable around a first axis so that the lock cylinder is placed in a first state; pivoting the lock cylinder in a first direction around the first axis with the first key directed into the keyway from a key removal position through a first range to thereby pivot an actuator assembly around the first axis between an unlocked position and a fully locked position as an incident of which a lock element is changed from an unsecured state into a secured state; pivoting the lock cylinder oppositely to the first direction around the first axis with the first key directed into the keyway through the first range to thereby place the lock cylinder in the key removal position so that the actuator assembly pivots through a second range from the unlocked position into the fully locked position; removing the first key with the lock cylinder in the key removal position; directing a second key having a second configuration into the keyway so that the lock cylinder is placed in a second state that is different than the first state; pivoting the lock cylinder in the first direction around the first axis with the second key directed into the keyway from the key removal position through the first range to thereby pivot the actuator assembly around the first axis between the unlocked position and the fully locked position; pivoting the lock cylinder oppositely to the first direction around the first axis with the second key directed into the keyway through the first range to thereby a) place the lock cylinder in the key removal position and b) pivot the actuator assembly from the fully locked position through less than the second range toward but not into the unlocked position; and removing the second key from the keyway with the lock cylinder in the key removal position.
The method may further include the step of relatively repositioning the lock cylinder and actuator assembly so that the second key cannot be directed fully into the keyway with the actuator assembly in the fully locked position and the lock cylinder in the key removal position.
The lock element may be changed between the unsecured state and secured state by either pivoting or translation.